What are the differences between these terms? Are they considered the same?
Voltage and electrostatic potential difference are the same thing, only using the word voltage specifies that you will be measuring the potential difference in units of volts.
Electrostatic potential is in principle a scalar field that exists at all points in space (assuming a quasi-static system). However we can't directly measure potential because its value may be changed by an arbitrary offset without changing any physically observable behavior of a system. Thus we only measure differences in the potential between two points, giving us the potential difference.